Use of Ivermectin

August 25, 2019

Because I have to keep my birds in pens to protect them from loose dogs and hawks, I have to also regularly worm them as well. Finding information on what to us and proper dosage often takes a lot of searching. I found this bit of information on the internet and found it helpful.. so posting it to share.

Originally posted on Backyard Chickens back in 2009.


Those of you that like ivermectin (Ivomec), the 1% cattle injectable solution works as well. The dose that I use on my Old English and Rosecomb Bantams is 0.1 ml by mouth per bird for 5 weeks. That is only 1/10th of a cc for ivermectin, just make sure you don't give more that 1/10th of a cc which is the same as 0.1 ml. So, these are the treatments that I use and tell my clients to use and we have excellent success with them. Hope this helps. Curtis Geary, VMD


Also several people use Ivomec wormer 1% water soluble or 5% oil based and put on the bird. Injectable 1% is used inside the bird in injection or in the water. And 5% oil based is used on the shoulder of the bird only. Not inside the bird. Directions for 5% ivomec with oil base put on shoulder only not internally.

  • 1 drop small bantam such as female OE
  • 2 drops large bantam male like OE
  • 3 drops most bantams 4 drops larger bantams and smaller commercial hens
  • 5 drops commercial large fowl and smaller large fowl 5 drops Large fowl chicken 7 drops larger males of large fowl breeds of chickens.

(A ) 5% oil type Ivomec stays on the birds for at least 6 weeks and is the reason it is only used on the out side under the feathers on the shoulder of the chickens. Slow release time.

(B) 1% water soulable is injectable and can be used in the water.

I will try to answer your questions as fully as I can. Since we are using ivermectin in an off-label fashion, first I need to say the birds being given ivermectin should not be used for food and the eggs should not be eaten. I am only saying this because I am a veterinarian and this is an off-label use and I am not aware of any controlled studies on the subject of withdrawal times. So for legal and safety reasons don't cull and eat these birds.

However, we eat beef, chicken, pork, etc. everyday that had previously been given ivermectin, but established withdrawal times have been (or should have been) followed. The information that is to follow is from my own personal experience and is not substantiated in any scientific journals as far as I know and is purely for informational use. (That's the end of my little legal/safety speech).

What can happen if too much ivermectin is given? Well, so far I haven't seen an overdose of ivermectin in chickens, however I will extrapolate from other species. Most of the signs have to deal with the neurologic (nervous) system and occasionally involve the digestive system. In the dogs that I have seen, in mild cases the dogs just act like they are "drunk". They stumble, have difficulty standing up and usually can't walk a straight line.

The moderate cases have this plus sometimes have blindness. Both of these cases usually resolve in 3-5 days with just some supportive care. The most severe case that I have seen was a 6 month old black lab puppy that ate the entire dose for a 1,000 pound horse after the horse spit out the wormer on the ground. It was comatose for 23 days, blind for another 10 days and is normal today (2 years later). So the overdose effects can vary, usually very dramatic, but usually resolve. However, death can occur with an overdose.

I like the 1% injectable form because I can draw up exactly 0.1 ml and give it in the breast muscle or by mouth. I also like it because I know that the ivermectin is then getting into the bloodstream. From other studies we know that ivermectin is absorbed into the bloodstream from the digestive tract. With the 5% oil based solution, it was made to be absorbed through the skin of cattle that has a fatty layer, oil glands, haired skin, sweat glands, etc. and this is totally different than poultry. I am not saying if it works or not. I've never tried it, for those reasons.

The dosages that you have listed look like they would be a good starting point. I would first try them on some culls rather than your best birds and if it works then continue with it. Since chickens have an oil gland near the tail the ivermectin may accumulate there and last longer than the injectable form, I really don't think (but don't know) if it is going to hang around on the body for 6 weeks though. I would be interested to know of anyone else's experiences though.


Those of you trying to make a product for leg mites, if you enjoy making home remedies and want the "organic" treatment go for it, but really, commercially available products are readily available and work very, very well. I bought some chickens at a local swap meet for one of my genetics projects and they had scaly leg mites. I sprayed the legs once with Ovitrol flea and tick spray by VetKem, gave them 0.1 ml ivermectin by mouth, tested them for Avian influenza, and Pollorum/Typhoid, vaccinated them for Laryngotracheitis, banded them (had to use big bands cause the leg mites were so bad) and placed them in my quarantine barn where they would reside for 6 weeks. About 4 weeks into the quarantine I noticed some of the birds bands were laying at the bottom of the cage.

When I went to put them back on I noticed that the scaly legs were completely healed and the reason that the bands were laying at the bottom to the cage is because the legs had returned to their normal size and the bands just slipped right off. All that from one application and one treatment of ivermectin.

Well, I hope I have answered your questions and I hope that I have not bored the rest of you with this long winded message. Thanks for the inquiry. Dr Curtis Geary

#IvermecforChickens #WormingChickens #ChickenWorming